--- a/ChangeLog	Sat Jan 05 11:02:51 2019 -0800
+++ b/ChangeLog	Sat Jan 05 18:02:32 2019 -0800
@@ -1,5 +1,15 @@
 2019-01-05  Paul Eggert  <eggert@cs.ucla.edu>
 
+	stdopen: modernize and simplify
+	* lib/stdopen.c: Update copyright date
+	Do not include sys/types.h; no longer needed these days.
+	(stdopen): Use C99-style decl in loop.  Return int errno
+	value, rather than just a bool.  Do not worry about fd mismatches,
+	since the caller cares only if 0, 1, 2 are occupied.
+	* lib/stdopen.h: No need to include <stdbool.h>.
+	* m4/stdopen.m4: Remove.
+	* modules/stdopen: New file.
+
 	stdopen: copy from last use in coreutils
 	* lib/stdopen.c, lib/stdopen.h, m4/stdopen.m4:
 	New files, taken from their last commit in coreutils

--- a/lib/stdopen.c	Sat Jan 05 11:02:51 2019 -0800
+++ b/lib/stdopen.c	Sat Jan 05 18:02:32 2019 -0800
@@ -1,6 +1,6 @@
 /* stdopen.c - ensure that the three standard file descriptors are in use
 
-   Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2005-2006, 2019 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -21,7 +21,6 @@
 
 #include "stdopen.h"
 
-#include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
@@ -31,44 +30,36 @@
    are in use.  Without this, each application would have to guard
    every call to open, dup, fopen, etc. with tests to ensure they
    don't use one of the special file numbers when opening a file.
-   Return false if at least one of the file descriptors is initially
-   closed and an attempt to reopen it fails.  Otherwise, return true.  */
-bool
+   Return zero if successful, an errno value if at least one of
+   the file descriptors is initially closed and could not be opened.  */
+
+int
 stdopen (void)
 {
-  int fd;
-  bool ok = true;
-
-  for (fd = 0; fd <= 2; fd++)
+  for (int fd = STDIN_FILENO; fd <= STDERR_FILENO; fd++)
     {
       if (fcntl (fd, F_GETFD) < 0)
-	{
-	  if (errno != EBADF)
-	    ok = false;
-	  else
-	    {
-	      static const int contrary_mode[]
-		= { O_WRONLY, O_RDONLY, O_RDONLY };
-	      int mode = contrary_mode[fd];
-	      int new_fd;
-	      /* Open /dev/null with the contrary mode so that the typical
-		 read (stdin) or write (stdout, stderr) operation will fail.
-		 With descriptor 0, we can do even better on systems that
-		 have /dev/full, by opening that write-only instead of
-		 /dev/null.  The only drawback is that a write-provoked
-		 failure comes with a misleading errno value, ENOSPC.  */
-	      if (mode == O_RDONLY
-		  || (new_fd = open ("/dev/full", mode) != fd))
-		new_fd = open ("/dev/null", mode);
-	      if (new_fd != fd)
-		{
-		  if (0 <= new_fd)
-		    close (new_fd);
-		  ok = false;
-		}
-	    }
-	}
+        {
+          /* Open /dev/null with the contrary mode so that the typical
+             read (stdin) or write (stdout, stderr) operation will fail.
+             With descriptor 0, we can do even better on systems that
+             have /dev/full, by opening that write-only instead of
+             /dev/null.  The only drawback is that a write-provoked
+             failure comes with a misleading errno value, ENOSPC.  */
+          int mode = fd == STDIN_FILENO ? O_WRONLY : O_RDONLY;
+          int full_fd = fd == STDIN_FILENO ? open ("/dev/full", mode) : -1;
+          int new_fd = full_fd < 0 ? open ("/dev/null", mode) : full_fd;
+          if (new_fd < 0)
+            return errno;
+          if (STDERR_FILENO < new_fd)
+            {
+              /* 0, 1, and 2 are already open somehow.
+                 Our is not to reason why.  */
+              close (new_fd);
+              return 0;
+            }
+        }
     }
 
-  return ok;
+  return 0;
 }

--- a/lib/stdopen.h	Sat Jan 05 11:02:51 2019 -0800
+++ b/lib/stdopen.h	Sat Jan 05 18:02:32 2019 -0800
@@ -1,13 +1,11 @@
 #ifndef STDOPEN_H
 # define STDOPEN_H 1
 
-# include <stdbool.h>
-
 # ifdef __cplusplus
 extern "C" {
 # endif
 
-bool stdopen (void);
+int stdopen (void);
 
 # ifdef __cplusplus
 }

--- a/m4/stdopen.m4	Sat Jan 05 11:02:51 2019 -0800
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,13 +0,0 @@
-#serial 1
-dnl Copyright (C) 2005 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-AC_DEFUN([gl_STDOPEN],
-[
-  AC_LIBSOURCES([stdopen.c, stdopen.h])
-  AC_LIBOBJ([stdopen])
-
-  dnl Prerequisites.
-])

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/stdopen	Sat Jan 05 18:02:32 2019 -0800
@@ -0,0 +1,24 @@
+Description:
+Arrange for stdin/stdout/stderr to be open.
+
+Files:
+lib/stdopen.c
+lib/stdopen.h
+
+Depends-on:
+fcntl
+unistd
+
+configure.ac:
+
+Makefile.am:
+lib_SOURCES += stdopen.c
+
+Include:
+"stdopen.h"
+
+License:
+GPL
+
+Maintainer:
+all